Weird Power

I have a 97 blazer. It starts and is running absolutely fine. The weird thing is that when I accelerate or give it gas, the lights get a little bit brighter and the battery and other gauges move. I know that this is related to the battery or alternator but i'm not sure which. The battery should be just fine. It's not even a year old and I have no problem starting the vehicle. Even the fan from the heat gets stronger when I give it gas. Do I have a bad alternator or what is the deal?

Its one of the 2. You should check your battery voltage to see if you have 12 volts or greater. Then check your out puit of your alternator. You should be putting out around 14 volts at idle. Anything less, you need to replace it.

Its one of the 2. You should check your battery voltage to see if you have 12 volts or greater. Then check your out puit of your alternator. You should be putting out around 14 volts at idle. Anything less, you need to replace it.

I dont think theres anything wrong. Mine does the same thing and has 13.7v at idle. You probably only have to rev it 2-300 rpm's and everything gets bright right? You've got alot going on when the heater is on, headlights, dashlights, and all the electronics in the truck. To properly test the battery and alternator, start the truck and put a volt meter to it. it should be about 13.5V. Next leave it run and turn on all of the other accessories. Measure for voltage again it should be anywhere from 13.5 to 14.5. :cya:

With everything on that you would use normally. Your lights shouldn't be dimming at idle. Unless you have some monster sound system that you pounding. I would do a complete voltage check on your alternator and battery.